America and the Left Half of the Bell Curve

Part I: IQ and Why We're Afraid to Talk About It

Part II: How the Other Half Lives

Why do half our kids score lower on tests than the other half? (OK, this is a joke. But why do some kids score poorly?) The Democrats blame test bias or underfunded schools or racism. The Republicans point to teachers' unions or gangsta rap or parents who don't help their kids with their homework. Everybody seems to think the problem of kids who perform poorly on tests will be solved by giving them even more tests.

Nobody is willing to publicly admit that a whole lot of young people just didn't draw winning hands in the genetic lottery for intelligence. To state this fact is considered insensitive and, horrors, bad for self-esteem. Maybe, but to ignore it is to acquiesce in the IQ elite setting policies that are starkly self-interested and uncharitable.

Several developments in recent decades threaten to undermine America's traditional knack for incorporating the great majority of citizens into the middle class. First, the relative economic value of a strong brain has risen dramatically compared to that of a strong back. Modern computers and telecommunications turbocharge the productive capacity of the intelligent. For example, Charles Murray pointed out in a follow-up to The Bell Curve, "In constant dollars, an engineer earned about $30,000 in 1952 compared with $20,000 for a manufacturing worker, which was not much different from the ratio at the beginning of the century. By 1988, the engineer earned almost $75,000 compared with $22,000 for the manufacturing worker." [Income Inequality and IQ, Charles Murray, August 1997]

Second, we've discovered that equality of opportunity can do surprisingly little to insure equality of result. One of the best methods for disentangling the effects of nature and nurture is to look at differences among children raised in the same household. I pointed out in my recent VDARE columns on the frustrations that feminist celebrities like Jodie Foster and Melissa Etheridge are likely to encounter when their designer babies don't live up to their hand-picked sperm donor dad's accomplishments.

Why not? The genes a child is dealt at conception don't come solely from those visible in his parents. Instead, they are randomly drawn from his entire family tree (weighted by closeness of relationship). Thus, as U. of Texas psychologist John Loehlin recently wrote to me: "The IQ difference between siblings is only about 30% smaller (on average) than that between any two randomly chosen people."

U. of Delaware psychometrician Linda S. Gottfredson noted in Society: "Those sibling differences [in IQ] are due mostly to the genetic differences among siblings, because their genotypes correlate only 0.5 on average... [The exceptions are identical twins. Their IQ's are much more similar because their genomes are the same.] Large IQ differences among siblings in turn produce large differences among them in school achievement and life outcomes. Those differences, in fact, are almost as large as those found between strangers whose IQs differ to the same degree."[Equal potential: A collective fraud. Society, 37(5), 19-28(PDF)]

Charles Murray recently quantified this in an ingenious study of pairs of American siblings raised together in non-poor homes. Murray described his findings in the Sunday Times of London in 1997:

Each pair consists of one sibling with an IQ in the normal range of 90-110, a range that includes 50% of the population. I will call this group the normals. The second sibling in each pair had an IQ either higher than 110, putting him in the top quartile of intelligence (the brights) or lower than 90, putting him in the bottom quartile (the dulls). These constraints produced a sample of 710 pairs. How much difference did IQ make? Earned income is a good place to begin. In 1993, when we took our most recent look at them, members of the sample were aged 28-36. That year, the bright siblings earned almost double the average of the dull: £22,400 compared to £11,800. The normals were in the middle, averaging £16,800. [IQ Will Put You In Your Place, Charles Murray, Sunday Times, UK, Day 25, 1997]

By the way, these earnings gaps are likely to widen with age, as the blue-collar workers' bodies wear out and therefore their incomes stagnate or fall.

Within families, parents do a better job of equalizing children's environments than any government less tyrannical than the Khmer Rouge could accomplish. Yet, even with the same upbringing, IQ differences are both substantial and play a huge role in the kids' prosperity as adults.

The plight of the left half of the Bell Curve is hardly restricted to ghetto blacks. It can afflict any family. Could your children end up with the fuzzy end of the IQ lollipop? Let's work the numbers assuming that that you and your spouse are both solidly ensconced in Murray's brights. Let's say you each have an IQ of 119, which puts you each at the 90th percentile. Well, due to regression toward the mean, the chance that your child will join you in the brights is less than fifty-fifty. In fact, more than one fourth of your children would be expected to inherit only double digit IQ's. A sobering 9% of your offspring are forecasted to end up among Murray's dulls with IQ's in the 80's or worse.

And unless your children marry smarter people than themselves, you can expect that fairly close to half of your grandchildren will have below average IQ's. (Of course, if you and your spouse both come from ethnic groups or family trees with an average IQ well above normal, the mean toward which your kids will regress will be higher.)

Of course, marrying a smart spouse is still the best, if not the only, way of smartening up your offspring. The edge you get, while not decisive in individual cases, would still be very well worth playing at the roulette wheel.

But I hope the exercise of contemplating our possible progeny can engender a little of the empathetic identification with the left half of the Bell Curve that is sorely lacking among the IQ overclass today. But whether their problems strike close to home for you or not, please do keep in mind that half of our fellow American citizens belong to this group today. Half of all Americans always will. Including, probably, some of your children or grandchildren.

How can we best help those who didn't roll sevens in the genetic crapshoot? That's what I'll consider in my next column.

[Steve Sailer [email him] is founder of the Human Biodiversity Institute and movie critic for The American Conservative. His website features his daily blog.]